This invention relates to a system for electrically firing a plurality of weapons such as rockets carried by rocket launchers on a military helicopter or other military vehicle, and including interrogation means for determining the availability of rockets ready to be fired and means for determining stray voltages in excess of safe levels indicative of a potentially dangerous condition when system power is turned on.
Rocket firing systems of the type described include an electrically operable igniter associated with each rocket. The igniter is in the form of an electrical filament or resistance element which is heated by the passage of a firing current through the igniter. The heat is sufficient to fire means which ignites the propulsion charge of the rocket. The igniters are connected to a firing circuit which includes a firing lead connected to one side of the igniters with the other side thereof connected to ground. The firing lead of each rocket is connected by suitable circuitry to firing control means, whereby a firing signal is applied to each firing lead under the control of an operator.
It is advantageous to include interrogation means in the system for providing information relating to the availability of rockets ready to be fired, and to test the system prior to rocket loading and when the system is powered to detect the presence of stray voltages which can cause premature and/or unwanted firing of a rocket. The information obtained from the aforenoted interrogating and testing may be applied to a computer for programming and display purposes.
Prior art systems of the type described, such as particularly described in U.S. Pat. No. 4,103,585 issued to Nelson D. Foley on Aug. 1, 1978, and assigned to BEI Electronics, Inc., Little Rock, Arkansas, feature a plurality of rocket firing circuits connected to respective igniters of a plurality of rockets. A plurality of switching devices are connected to respective firing circuits and a plurality of signal circuits are connected between a signal source and respective switching devices. Each signal circuit includes indicating means for indicating the presence or absence of a signal current between a signal source and a corresponding igniter.
The invention described in the aforenoted copending U.S. Application Ser. No. 191,642 is an improvement over the prior art device in that it features a single signal circuit and a single indicating means to provide a more accurate, more reliable and more economical system. In combination with the above features, the present invention provides means for testing for stray voltages which may be indicative of a dangerous system condition.